Rosuvastatin (7-[4-(4-fluorophenyl)-6-isopropyl-2-(N-methyl-N-methylsulfonylamino) pyrimidin-5-yl]-(3R,5S)-dihydroxy-(E)-6-heptenoic acid) calcium is an HMG-CoA reductase inhibitor, developed by Shionogi for the once daily oral treatment of hyperlipidaemia (Ann Rep, Shionogi, 1996; Direct communications, Shionogi, 8 Feb. 1999 & 25 Feb. 2000). Rosuvastatin calcium has the following chemical formula:

Rosuvastatin calcium is marketed under the name CRESTOR for treatment of a mammal such as a human. According to the maker of CRESTOR, it is administered in a daily dose of from about 5 mg to about 40 mg for LDL cholesterol reduction.
U.S. Pat. No. 5,260,440 (EP0521471A1) (US '440), discloses the synthesis of rosuvastatin from the intermediate 3(R)-3(tert-butyldimethylsilyloxy)-5-oxo-6-triphenyl-phoporanylidene hexanoate. PCT publication No. WO 03/097614 discloses the synthesis of rosuvastatin from the intermediate (3R)-3-(tert-butyldimethylsilyloxy)-5-oxo-6-triphenyl-phosphoralydene hexanoate, disclosed in US '440 patent.
PCT publication No. WO 03/087112 discloses the synthesis of rosuvastatin from a different intermediate, (3R)-3-(t-butyldimethylsilyloxy)-6-dimethoxyphosphinyl-5-oxohexanate (TSPH), which was synthesized from 3-hydroxy diethyl glutarate via partial hydrolysis by a microorganism to obtain enantiomerically pure glutaric acid derivative according to Scheme 1:
The process of PCT publication No. WO 03/087112 may not be desirable on an industrial scale. For example, it requires the use of an expensive microorganism such as CLS-BC-14011 during the partial hydrolysis of 3-hydroxy diethyl glutarate. Additionally, the process uses a hazardous reaction, such as isobutylene gas during esterification of ethyl-(3S)-3-hydroxyglutaric acid in the presence of sulphuric acid, and the purification of TSPH by column chromatography is commercially difficult.
US publication No. 2005/0070605A1 discloses the enantioselective opening of 3-hydroxyprotected glutaric anhydride by phenyl ethylamine to form an amide bond, and further converting it to HMG-CoA reductase inhibitor. The process may have problems such as breaking of the phenyl ethyl amide bond in the final step of producing cerivastatin and the problematic removal of phenylethylamine after breaking of the amide linkage in the synthesis of pitavastatin.
PCT publication No. WO 2006/021326 discloses the opening of 3-hydroxy protected glutaric anhydride by methanol to yield racemic methyl 3(±)-3-(t-butyl dimethylsilyloxy)-6-dimethoxy-phosphinyl-5-oxohexante, and the preparation of racemic methyl (3R)-3-(t-butyl dimethylsilyloxy)-6-dimethoxy-phosphinyl-5-oxohexante.
U.S. Pat. No. 5,354,879 discloses the preparation of both methyl (3R)-3-(t-butyl dimethylsilyloxy)-6-dimethoxy-phosphinyl-5-oxohexante and 3(R)-3(tert-butyldimethylsilyloxy)-5-oxo-6-triphenyl-phoporanylidene hexanoate from (3R) 3-[(tert-butyldimethylsilyl)oxy]-glutaric acid 1-(R)-(−)-mandelate and (3S) 3-[(tert-butyldimethylsilyl)oxy]-glutaric acid 1-(S)-(+)-mandelate, respectively. The disclosed process employs explosive and toxic materials, such as diazomethane, during the preparation of methyl-(3R)-3-(t-butyl dimethylsilyloxy)-6-dimethoxy-phosphinyl-5-oxohexante(esterification). Moreover, the yield of the above steps is low, and thus the process may not suitable for industrial and commercial use.
J. Org. Chem. (1991) 56:3744-47 discloses the preparation of (3R)-3-(t-butyl dimethylsilyloxy)-6-dimethoxy-phosphinyl-5-oxohexante from 3-hydroxy protected glutaric anhydride. The disclosed process which involves using hazardous reactions, such as use of N2O4 oxidation, followed by a hydrogenation reaction to cleave the amino group of the resolving agent, and use of diazomethane. The process also uses an expensive palladium catalyst which could remain as an impurity in the final product.